JP4648109B2 - Method for molding synthetic resin injection molded product and injection mold apparatus - Google Patents

Description

  The present invention relates to a method for molding a synthetic resin molded product in which a secondary injection molded portion is integrated with a primary injection molded portion, and an injection mold apparatus.

  Conventionally, a part of the overlapping part 3b of the secondary injection molding part 2 is integrated with the end of the outer surface of the primary injection molding part 1 and the non-overlapping part 3a of the secondary injection molding part 2 is the primary injection molding part 1. Patent Document 1 discloses a molding method and an injection mold apparatus 5 for molding a synthetic resin injection molded product 4 projecting from the end of the mold.

  FIG. 12 to FIG. 15 schematically show the order of manufacturing the synthetic resin injection molded product 4 using the conventional injection mold apparatus 5 shown in Patent Document 1.

  That is, as shown in FIG. 12, the fixed mold part 6a and the movable mold part 6b are closed and the slide core 7 is advanced to form the primary injection molding cavity part 8, and then as shown in FIG. The first resin 10 is injected into the primary injection molding cavity 8 by primary injection molding, and then the slide core 7 is moved backward as shown in FIG. 14 to form the secondary injection molding cavity 13. Next, as shown in FIG. 15, the second resin 14 is injected into the secondary injection molding cavity 13 by secondary injection molding to form the secondary injection molding portion 2 and one of the secondary injection molding portions 2. The part is overlapped and integrated with the end of the outer surface of the primary injection molded part 1.

However, in the above-described conventional example, after the first resin 10 is molded in the primary injection molding cavity 8 by primary injection molding, the slide core 7 is retracted to form the secondary injection molding cavity 13. However, during this time, the primary injection molding part 1 formed in the primary injection molding cavity part 8 begins to harden and tends to shrink. In this case, since the restriction | limiting by the slide core 7 is cancelled | released in the site | part facing the slide core 7 of the edge part of the primary injection molding part 1, the edge part of the primary injection molding part 1, and the slide core 7 of the fixed mold part 6a A gap (indicated by “A” in FIG. 14) is generated due to the shrinkage of the primary injection molded portion 1 between the opposed portions. For this reason, when the second resin 14 is injection-molded by secondary injection molding as shown in FIG. 15 in the cavity for secondary injection molding formed by retreating the slide core 7, the second resin 14 is the primary resin. The resin enters the gap A between the end of the injection molded part 1 and the fixed mold part 6 (B in FIG. 15 indicates the second resin 14 that has entered the gap A), and the synthetic resin molded product 4 is as designed. There was a problem that the product could not be molded into the external appearance, and the external appearance deteriorated and the commercial value was lowered.
JP-A-8-118421

  The present invention has been invented in view of the above-described conventional problems, and in forming a synthetic resin molded product in which a secondary injection molding part is integrated integrally with a primary injection molding part, the slide core is moved backward to form a second product. When forming the cavity for the next injection molding, no gap is generated between the end of the primary injection molded part, which is no longer regulated by the slide core, and the mold part. It is an object of the present invention to provide a method for molding a synthetic resin injection molded product and an injection mold apparatus capable of molding the synthetic resin molded product.

Molding process of synthetic resin injection molded article according to the present invention in order to solve the above problems, an end portion of one of the outer surface of the primary injection molding unit 1 of the outer surface of the adjacent rigid ends are located at a distance A synthetic resin injection molded product 4 in which both sides of the soft secondary injection molding part 2 are overlapped and integrated and a non-overlapping part 3 of the secondary injection molding part 2 is a foldable hinge part is used as an injection mold apparatus. 5, a plurality of mold parts 6 in the injection mold apparatus 5, a slide core 7 that can be moved forward and backward provided in the mold part 6, and a slide core 7. And a support pin 9 provided so as to be relatively movable in the moving direction of the slide core 7. The injection mold apparatus 5 including a plurality of mold parts 6 is closed and the slide core 7 is advanced to a plurality. Mold part 6, the front surface of the slide core 7, and the support pins 9. And forming a plurality of primary injection molding cavity 8 formed by surrounded by the end surface space so that the ends of adjacent primary injection molding cavity 8 is positioned at a distance, each primary injection The front end surface of the support pin 9 is positioned in the vicinity of the end of the molding cavity 8 , and a plurality of primary injections are performed by injecting a hard first resin 10 into the plurality of primary injection molding cavities 8 by primary injection molding. The front end face of the molded part 1 is molded, and then the primary injection molded part 1 which has been cured while the mold part 6 is closed is regulated by the plurality of mold parts 6 and the support pins 9 are not moved. curing in a state of supporting a part of the LSP starts was the primary injection molding unit 1, it is retracted only slide core 7 part at the front end surface of at least the supporting pins 9 of each primary injection molding unit 1 is supported each exposing the outer surface end portion As double face 12, the mold portion 6 and the slide core 7 and the primary injection molding unit 1 of the overlapping surface 12 two spans between the ends of the enclosed adjacent primary injection molding unit 1 by the primary injection molding cavity 13 Next, the primary injection molding part 1 that has been cured in this way is regulated by closing the mold parts 6, and at the part that becomes the overlapping surface 12 that is not regulated by the mold part 6. In a state where a part is supported by the front end surface of the support pin 9, the secondary injection molding portion 2 is formed by injecting a soft second resin 14 into the secondary injection molding cavity portion 13 by secondary injection molding. The both sides of the secondary injection molding part 2 are overlapped and integrated with each overlapping surface 12 of the adjacent primary injection molding part 1 respectively .

According to such a method, after the first resin 10 is injected by primary injection molding into the primary injection molding cavity 8 adjacent to each other at a distance , the slide core 7 is retracted to perform secondary injection molding cavity. When forming 13, the primary injection molding part 1 which has been cured while the plurality of mold parts 6 are closed is regulated by the plurality of mold parts 6 and cured at the front end face without moving the support pin 9 In the state in which a part of the primary injection molding part 1 that has started is supported, only the slide core 7 is retracted, and an outer surface end partly supported by at least the front end face of the support pin 9 of each primary injection molding part 1 The secondary part straddling between the end parts of the adjacent primary injection molding part 1 surrounded by the mold part 6, the slide core 7, and the overlapping surface 12 of the primary injection molding part 1 is exposed as the overlapping surface 12. Form injection molding cavity 13 When the primary injection in the injection molded molding cavity portion 8 a primary injection end of the molding section 1 is regulated by the slide core 7 is released, the end of the primary injection molding unit 1 by the contraction of the primary injection molding unit 1 A gap is likely to be formed between the mold part 6 and the mold part 6, but a part of the overlapping surface 12 is supported by the front end surface of the support pin 9, so that the slide core 7 is retracted and the restriction by the slide core 7 is released. Even in this state, the support pin 9 restricts the contraction of the end of the primary injection molded part 1 to prevent a gap from being formed between the end of the primary injection molded part 1 and the mold part 6, and thereafter In the secondary injection molding, the second resin 14 does not enter between the primary injection molding part 1 and the mold part 6, whereby a synthetic resin molded product having an appearance as designed can be molded. In particular, the secondary injection molded parts 1 that are adjacent to each other at a distance are molded by injection molding of the hard first resin 10, and the secondary side is overlapped and integrated with each overlapping surface 12 of the adjacent primary injection molded part 1. Since the injection-molded part 2 is formed by injection molding of the soft second synthetic resin 14, the hard primary injection-molded parts 1 whose ends are adjacent to each other at a distance from each other and a flexible hinge whose middle part can be bent and The synthetic resin injection molded product 4 connected and integrated by the secondary injection molding part 2 can be molded as designed.

Further, the injection mold apparatus 5 of the present invention comprises a mold apparatus comprising a plurality of mold parts 6, a slide core 7 which is provided on the mold part 6 and can be moved forward and backward, and is provided on the slide core 7. A support pin 9 that is movable relative to the slide core 7, a first gate 15 for injecting a hard first resin 10, and a second for injecting a soft second resin 14. The plurality of mold parts 6 are closed and the slide core 7 is advanced to form a plurality of spaces surrounded by the front surface of the slide core 7 and the front end surface of the support pin 9. Then, the plurality of spaces are used as primary injection molding cavities 8 for primary injection of the first resin 10 from the first gate 15 to form a plurality of primary injection molding portions 1, and the support pins. 9 near the end of the primary injection molding cavity 8 The plurality of primary injection molding cavities 8 are formed such that the ends of the adjacent primary injection molding cavities 8 are spaced apart, and the plurality of mold parts 6 are closed. The primary injection-molded part 1 that has been cured is regulated by a plurality of mold parts 6 and slides in a state where a part of the outer surface of the primary injection-molded part 1 is supported by the front end face without moving the support pin 9. Only the core 7 is retracted, and the overlapping surface 12 composed of the exposed surface of the outer surface end part of which is supported at least by the front end surface of the support pin 9 of the primary injection molded part 1, and the mold part 6 are retracted. A cavity portion for secondary injection molding 13 formed of a space surrounded by the slide core 7 is formed, and is adjacent to the projection surface of the cavity portion 13 for secondary injection molding projected from the moving direction of the slide core 7. Duplicate primary injection molding part 1 12 is characterized in that formed by setting to be positioned respectively.

In this way, a plurality of primary injection molding cavities 8 for molding a plurality of primary injection molding parts 1 are formed such that the ends of adjacent primary injection molding cavities 8 are located at a distance from each other. When the slide core 7 is provided with a support pin 9 that is movable relative to the slide core 7 in the moving direction of the slide core 7 and the slide core 7 is moved backward to form the secondary injection molding cavity 13. In addition, the primary injection molded part 1 that has been cured while the mold parts 6 are closed is regulated by the plurality of mold parts 6 and the front end surface of the primary injection molded part 1 is moved without moving the support pins 9. By supporting the primary injection molding part 1 with the support pin 9 by retracting only the slide core 7 with a part of the outer surface of the primary part being supported, the ends are adjacent to each other with a distance therebetween. Secondary injection of injection molding part 1 In forming a synthetic resin injection molded article 4 linked together in the form section 2, and a gap created between the primary injection molding section ends and the mold portion 6 of 1 adjacent, two in a subsequent order The injection mold apparatus 5 in which the second resin 14 does not enter between the primary injection molding part 1 and the mold part 6 during the injection molding can be provided. Also, a synthetic resin injection molded product 4 is formed by joining and integrating hard primary injection molded parts 1 which are adjacent to each other at a distance from each other by a soft secondary injection molded part 2 whose middle part can be bent. In addition to molding, the second resin 14 does not enter between the primary injection molded part 1 and the mold part 6 during the secondary injection molding, and the synthetic resin molded product 4 having the designed appearance is molded. An injection mold device 5 can be provided.

The method for molding a synthetic resin injection molded product according to the present invention closes an injection mold apparatus comprising a plurality of mold parts and advances the slide core to advance the plurality of mold parts, the front surface of the slide core, and a support pin. And forming a plurality of primary injection molding cavities formed by a space surrounded by the front end surface so that the ends of adjacent primary injection molding cavities are located at a distance from each other and each primary injection The front end surface of the support pin is positioned near the end of the molding cavity, and a plurality of primary injection molding parts are formed by injecting a hard first resin into the plurality of primary injection molding cavities by primary injection molding. Next, primary injection molding in which hardening is started on the front end surface of the primary injection molding part, which is controlled by a plurality of mold parts and the support pin is not moved, while the mold part is closed with the mold closed. Support a part of the department In this state, only the slide core is retracted to expose at least the outer surface end portion supported by the front end surface of the support pin of each primary injection molding portion, and the mold portion, the slide core, and the above as overlapping surfaces, respectively. Form a secondary injection molding cavity that spans between the ends of adjacent primary injection molding parts surrounded by the overlapping surfaces of the primary injection molding parts, and then set the primary injection molding part that has been cured in this way. While restricting by closing the molds of multiple mold parts, in the part of the overlapping surface that is not regulated by the mold parts, a part of it is supported by the front end face of the support pin, and the cavity part for secondary injection molding is soft The second resin is injected by secondary injection molding to form a secondary injection molded part and both sides of the secondary injection molded part are overlapped and integrated with each overlapping surface of the adjacent primary injection molded part. Adjacent parts apart The primary injection molding portions of the rigid intermediate portion can be easily molded integrally connected by a synthetic resin injection molded article in the secondary injection molding unit became hinge portion of the freely flexible bending. In addition, the primary injection molded part that has been cured while the mold part is closed is regulated by a plurality of mold parts, and the primary injection molded part that has been cured at the front end surface thereof without moving the support pin. Since only the slide core is retracted while supporting the part, even if the slide core is retracted and the restriction of the overlapping surface of the primary injection molding part by the slide core is released, the overlapping surface is supported by the support pin. The shrinkage of the end of the primary injection molding part is restricted, and the second resin does not enter between each primary injection molding part and the mold part, and the appearance as designed is obtained. As a result, according to the present invention, a synthetic resin injection molded product obtained by connecting and integrating hard primary injection molded parts with a secondary injection molded part that is a flexible hinge whose middle part can be freely bent has an appearance as designed. Can be molded.
Further, the injection mold apparatus of the present invention is a synthetic resin injection molding in which the hard primary injection molding parts are connected and integrated by a secondary injection molding part which is a flexible hinge whose middle part can be bent by the above method. An apparatus capable of forming an article can be provided.

  Hereinafter, the present invention will be described based on embodiments shown in the accompanying drawings.

  As shown in FIG. 5, the synthetic resin injection molded product 4 molded by the synthetic resin injection molded product molding method and the injection mold apparatus of the present invention has at least one of the outer surfaces of the primary injection molded portion 1. A part of the secondary injection molding part 2 (overlapping part 3b) is overlapped and integrated at the end, and the non-overlapping part 3a of the secondary injection molding part 2 projects beyond the end of the primary injection molding part 1. is there.

  In the embodiment shown in FIG. 5, an example is shown in which the primary injection molding parts 1 adjacent to each other at a plurality of distances are integrally connected by the secondary injection molding part 2, and in this example, for example, PP (polypropylene) In addition to forming the primary injection molded part 1 with the first resin 10 made of a hard resin such as PE (polyethylene), HDPE (high density polyethylene), PC (polycarbonate), PVC (vinyl chloride resin), ABS resin, Secondary injection molding part 2 is formed with second resin 14 made of soft resin such as TPE (elastomer), LDPE (low density polyethylene), EVA (ethylene vinyl acetate copolymer), etc., and secondary injection made of soft resin The example in which the non-overlapping part 3a of the shaping | molding part 2 comprises the hinge part is shown.

  FIG. 1 shows an example of an injection mold apparatus 5 of the present invention for molding the synthetic resin molded product 4 shown in FIG.

  The mold apparatus 5 for injection molding includes a slide core 7 (indicated by an arrow A in FIG. 1 indicating an advance direction and an arrow B indicating a retract direction) provided in the mold portion 6 and a first resin 10. A first gate 15 for injecting and a second gate 16 for injecting the second resin 14 are provided.

  The mold part 6 includes a fixed mold part 6a and a movable mold part 6b. A recess 18 is provided on a surface of the movable mold part 6b facing the fixed mold part 6a. The slide core 7 is housed in such a manner that it can move forward and backward.

  Pin holes 11 are formed on both sides of the slide core 7, and support pins 9 are provided in the pin holes 11 so as to be relatively movable in the moving direction of the slide core 7. The support pin 9 is movable in the same direction as the moving direction of the slide core 7.

  In the present invention, the movable mold part 6b is movable in the lateral direction (horizontal direction) or the vertical direction (vertical direction) with respect to the fixed mold part 6a, and by moving the movable mold part 6b. The mold is closed and the mold is opened. Moreover, the slide core 7 is movable in the same direction as the movable direction of the movable mold part 6b with respect to the movable mold part 6b.

  With the fixed mold part 6a and the movable mold part 6b closed and the slide core 7 moved forward, the fixed mold part 6a, the movable mold part 6b, the front surface of the slide core 7 and the support pins 9 are provided. A space surrounded by the front end face is formed, and this space becomes the primary injection molding cavity 8. A plurality of the primary injection molding cavities 8 are formed, and the ends of the adjacent primary injection molding cavities 8 are separated by a distance. The slide core 7 extends between the end portions of the adjacent primary injection molding cavities 8, and the center portion of the front surface of the slide core 7 is adjacent to each of the primary injection molding cavities adjacent to the fixed mold portion 6 a. The both sides of the front surface of the slide core 7 are opposed to the portion 6a1 between the eight end portions, and constitute an inner surface on one side of the end portion of the primary injection molding cavity portion 8 adjacent thereto. Further, the support pins 9 provided on both sides of the slide core 7 are positioned at portions constituting the inner surface on one side of the end portion of the adjacent primary injection molding cavity 8 on both sides of the slide core 7, respectively. The front end surfaces of the pins 9 are located in the vicinity of the end portions of the adjacent primary injection molding cavities 8.

  The plurality of primary molding cavities 8 are formed by providing a plurality of cavity forming recesses 17 on one or both of the opposing surfaces of the fixed mold part 6a to the movable mold part 6b. In the embodiment of the accompanying drawings, an example is shown in which a plurality of cavity forming recesses 17 are formed in the fixed mold part 6a.

  Further, after the first resin 10 is injected into the primary injection molding cavity 8 by primary injection molding to form the primary injection molding part 1, the mold closing of the fixed mold part 6a and the movable mold part 6b is continued. In addition, the slide core 7 is retracted in a state in which a part of the outer end portion of the primary injection molding portion 1 is supported by the front end surface without moving the support pin 9, so that the adjacent primary injection molding cavity portion 8. The end portions of one of the outer surfaces of the primary injection molded portions 1 formed inside are respectively exposed, and the primary injection molded portions 1 molded in the adjacent primary injection molding cavities 8 respectively. A space is formed to be a secondary injection molding cavity 13 surrounded by the overlapping surface 12 that is an exposed surface and the mold part 6.

  The first gate 15 and the second gate 16 are each provided in the fixed mold portion 6a, and a plurality of the first gates 15 are provided, and the first gate is provided in each of the plurality of primary injection molding cavities 8. 15 is open. The second gate 16 opens to a portion 6a1 between the end portions of the adjacent primary injection molding cavities 8 of the fixed mold portion 6a to close the mold portion 6 and advance the slide core 7. In this state, the front end surface of the slide core 7 comes into contact with the second gate 16 and closes, and the mold portion 6 is closed and the slide core 7 is moved backward to make the cavity portion for secondary injection molding. The second gate 16 is configured to open to the secondary injection molding cavity 13 in a state in which 13 is formed.

  The synthetic resin injection molded product 4 is molded using the injection molding die device 5 as described above as follows.

  First, as shown in FIG. 1, with the plurality of mold parts 6 closed and the slide core 7 advanced, the fixed mold part 6a, the movable mold part 6b, the front surface of the slide core 7, and the support pins 9 is formed as a primary injection molding cavity 8, and as shown in FIG. 2, the first resin 10 is fed from the first gate 15 to the primary injection molding cavity 8. A primary injection process is performed in which the primary injection molding part 1 is molded by injection by primary injection molding.

  By this primary injection molding, the primary injection molding part 1 is molded in the cavity part 8 for primary injection molding.

  Next, as shown in FIG. 3, a plurality of mold parts 6 are closed, and a part of the outer end of the primary injection molded part 1 is supported by the front end face without moving the support pin 9. In this state, the slide core 7 is moved backward to form the secondary injection molding cavity 13. In this case, when the slide core 7 is retracted, at least the outer surface end portion of the primary injection molding portion 1 supported by the front end surface of the support pin 9 is exposed as the overlapping surface 12. A secondary injection molding cavity portion 13 is formed which is surrounded by the slide core 7 and the overlapping surface 12 of the primary injection molding portion 1 and has a space into which the support pin 9 projects.

  In this case, the restriction by the slide core 7 is released on the end side of the primary injection molded part 1 injection-molded in the primary injection molding cavity 8, and therefore the primary injection molded part 1 is contracted by the primary injection molded part 1. However, in the present invention, when the slide core 7 is retracted as described above, the support by the support pins 9 is maintained as described above. Since the slide core 7 is retracted, even if the slide core 7 is retracted and the restriction by the slide core 7 is released, contraction of the end portion of the primary injection molded portion 1 is restricted by the support pin 9. Therefore, when the slide core 7 is retracted after the primary injection molding to form the secondary injection molding cavity 13, it is possible to prevent a gap from being generated between the end of the primary injection molding part 1 and the mold part 6. Is done.

  Next, as shown in FIG. 4, the second resin 14 is injected from the second gate 16 into the secondary injection molding cavity 13 formed as described above by secondary injection molding, and is subjected to secondary injection molding. The overlapping part 3b at both ends of the secondary injection molding part 2 is overlapped and integrated with the overlapping surface 12 of the outer surface end part of one side of the primary injection molding part 1 adjacent to the part 2 while being molded.

  As described above, when the slide core 7 is moved backward to form the secondary injection molding cavity portion 13, the restriction of the overlapping surface 12 of the primary injection molding portion 1 by the slide core 7 is released. In the invention, since a part of the overlapping surface 12 of the primary injection molding part 1 is continuously supported by the front surface of the support pin 9, the contraction of the end of the primary injection molding part 1 is restricted, and the primary injection molding part 1 Since a gap is prevented from being generated between the end portion and the mold portion 6, the second resin 14 does not enter between the primary injection molded portion 1 and the mold portion 6 by secondary injection molding. .

For this reason, according to the present invention, the second resin 14 that forms the secondary injection molded portion 2 does not ooze out from the opposing end surfaces of the primary injection molded portions 1 that are adjacent to each other at a distance. Thus, the synthetic resin molded article 4 having an appearance as designed and excellent in aesthetic appearance can be formed.

  After the secondary injection molding is performed as described above, a mold release step is performed in which the mold apparatus 5 for injection molding is opened and the synthetic resin injection molded product 4 is taken out.

  From these series of mold closings, a series of processes such as primary injection molding, secondary injection molding, and mold release process are executed under the control of a control unit (not shown).

By the way, in the present invention, as shown in FIG. 5, the primary injection molding is performed by laminating and overlapping the overlapping portions 3 b on both sides of the secondary injection molding portion 2 at the ends of the primary injection molding portions 1 adjacent to each other at a distance. in the first resin 10 is a hard resin for forming the molded portion 1, the second resin 14 to form a secondary injection molding unit 2 has particular features that are soft resin, the secondary injection molded part 2 non-overlapping portions 3a in the middle portion (that is, non-overlapping portions 3a in the middle portion of the secondary injection molding portion 2 are portions protruding from the end portions of both primary injection molding portions 1) are hinge portions and are rigid The primary injection molded parts 1 made of the first resin 10 can be integrally connected to each other by a hinge part made of the soft second resin 14 so as to be bent .

  In addition, when both ends of the slide core 7 are opposed to the ends of the adjacent primary injection molding cavities 8 as shown in FIG. 6, among the adjacent primary molding cavities 8 out of both sides of the slide core 7. When the width of one side part that is a part of one of the primary molding cavities 8 is wide and the width of one side part that is a part of the other primary molding cavities 8 is narrow, In the case where there is no possibility that the end of the primary injection molding part 1 contracts and a gap is formed between the primary injection molding part 1 and the mold part 6 even if the slide core 7 is retracted, the slide core 7 is Supports only on the wide side of the side where the end of the primary injection molded part 1 shrinks and a gap may be formed between the primary injection molded part 1 and the mold part 6 even if it is retracted. A pin 9 may be provided.

  7 to 11 show another embodiment of the present invention.

  In the above-described embodiment, as shown in FIG. 1, the slide core 7 is closed and the slide core 7 is moved forward to form the primary injection molding cavity 8, and the slide core is formed. 7 shows an example in which the front surface of the support pin 9 and the front end surface of the support pin 9 are flush with each other. In this embodiment, the fixed mold portion 6a and the movable mold portion 6b are formed as shown in FIG. In a state where the slide core 7 is advanced and the cavity portion 8 for primary injection molding is formed, the support pin 9 is immersed in the pin hole 11 and the front end surface of the support pin 9 is more than the front surface of the slide core 7. An example of retreating is shown. Therefore, in this embodiment, a space surrounded by the fixed mold portion 6a, the movable mold portion 6b, the front surface of the slide core 7, the front end surface of the support pin 9, and the inner wall of the front end portion of the pin hole 11 is formed. The primary injection molding cavity portion 8 is formed, and the primary injection molding portion 1 formed by primary injection molding of the first resin 10 in the primary injection molding cavity portion 8 as shown in FIG. The protrusion 1a is formed by the first resin 10 filled in the pin hole 11 portion ahead of the front end surface of the support pin 9, and the secondary injection is performed by retracting the slide core 7 as shown in FIG. When the molding cavity portion 13 is formed, the projecting surface of the projecting portion 1 a is supported by the front end surface of the support pin 9. After that, as shown in FIG. 10, the second resin 14 is subjected to secondary injection molding in the secondary injection molding cavity 13 to form the secondary injection molding portion 2, and the outer end portion of the primary injection molding portion 1 is overlapped. When the overlapping portion 3b at the end of the secondary injection molding portion 2 is integrated with the surface 12 in an overlapping manner, the protrusion 1a is embedded in the secondary injection molding portion 2 so that the primary injection molding portion 1 is integrated. And the secondary injection molding part 2 are more firmly integrated. As shown in FIG. 11, the protrusion 1a has a protrusion length that is the same as the thickness of the secondary injection molding part 1 so that the protrusion surface of the protrusion 1a and the outer surface of the secondary injection molding part 2 are flush with each other. Alternatively, the protruding length of the protruding portion 1a is shorter than the thickness of the secondary injection molded portion 1, and a recess after the support pin 9 is pulled out is formed on the outer surface of the secondary injection molded portion 1. You may be made to do.

It is sectional drawing of the mold closing state of the injection mold apparatus of this invention. It is sectional drawing of the injection mold apparatus of the state which filled the 1st resin by primary injection molding to the primary injection molding cavity part same as the above, and formed the primary injection molding part. It is sectional drawing of the injection mold apparatus of the stage which formed the cavity part for secondary injection molding same as the above. It is sectional drawing of the injection mold apparatus of the stage which filled the 2nd resin by secondary injection molding in the secondary injection molding cavity part same as the above, and formed the secondary injection molding part. An example of the synthetic resin injection-molded product molded by the same as above is shown, (a) is a perspective view, and (b) is a cross-sectional view. (A) is sectional drawing of the mold closing state of other embodiment of the injection mold apparatus of this invention, (b) is sectional drawing of the synthetic resin injection molded product shape | molded by the same as the above. It is sectional drawing of the mold closing state of other embodiment of the injection molding die apparatus of this invention. It is sectional drawing of the injection mold apparatus of the state which filled the 1st resin by primary injection molding to the primary injection molding cavity part same as the above, and formed the primary injection molding part. It is sectional drawing of the injection mold apparatus of the stage which formed the cavity part for secondary injection molding same as the above. It is sectional drawing of the injection mold apparatus of the stage which filled the 2nd resin by secondary injection molding in the secondary injection molding cavity part same as the above, and formed the secondary injection molding part. An example of the synthetic resin injection-molded product molded by the same as above is shown, (a) is a perspective view, and (b) is a cross-sectional view. It is sectional drawing of the mold closing state of the injection molding die apparatus of a prior art example. It is sectional drawing of the injection mold apparatus of the state which filled the 1st resin by primary injection molding to the primary injection molding cavity part same as the above, and formed the primary injection molding part. It is sectional drawing of the injection mold apparatus of the stage which formed the cavity part for secondary injection molding same as the above. It is sectional drawing of the injection mold apparatus of the stage which filled the 2nd resin by secondary injection molding in the secondary injection molding cavity part same as the above, and formed the secondary injection molding part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Primary injection molding part 2 Secondary injection molding part 3a Non-overlapping part 4 Synthetic resin injection molded article 5 Injection molding die apparatus 6 Mold part 7 Slide core 8 Cavity part for primary injection molding 9 Support pin 10 First resin 12 Overlapping surface 13 Cavity for secondary injection molding 14 Second resin 15 First gate 16 Second gate

Claims (2)

The ends of one of the outer surfaces of the adjacent hard primary injection-molded parts, the ends of which are spaced apart from each other, are overlapped and integrated with both sides of the soft secondary injection-molded part. A molding method for molding a synthetic resin injection molded product in which a non-overlapping portion of the non-overlapping portion becomes a foldable hinge portion with an injection mold device, wherein the injection mold device includes a plurality of mold portions, A forward and backward slide core provided in the mold part and a support pin provided to be movable relative to the slide core in the moving direction of the slide core are provided.
The injection mold apparatus comprising a plurality of mold parts is closed and the slide core is advanced to form a space surrounded by the plurality of mold parts, the front surface of the slide core, and the front end face of the support pin. A plurality of primary injection molding cavities are formed so that the ends of adjacent primary injection molding cavities are spaced apart from each other, and the support pins are arranged near the ends of the primary injection molding cavities . Position the front end face ,
Injection of hard first resin into multiple primary injection molding cavities by primary injection molding to form multiple primary injection molding parts, and then primary injection with the mold part closed and curing started With the molding part restricted by a plurality of mold parts and supporting the part of the primary injection molding part that has been cured on the front end face without moving the support pin, only the slide core is retracted to make each primary as each overlap surface by exposing at least the outer surface end portion at the front surface is supported in the support pins of the injection molding unit, surrounded by a mold portion and the slide core and the overlapping surface of the primary injection unit A secondary injection molding cavity is formed between the ends of adjacent primary injection molding parts , and then the primary injection molding part, which has been cured in this way, is regulated by closing a plurality of mold parts. , It becomes an overlapping surface not regulated by the mold part While supporting a part in the front end face of the support pin in position, to form a secondary injection molding section by injection by the secondary injection molding a second resin of the soft into the cavity portion for secondary injection molding A method for molding a synthetic resin injection molded product, wherein both sides of a secondary injection molded portion are overlapped and integrated with each overlapping surface of adjacent primary injection molded portions . An injection mold apparatus for molding the synthetic resin injection-molded product according to claim 1, wherein the mold apparatus comprises a plurality of mold parts, and a slide core that is provided on the mold part and is movable forward and backward. A support pin provided on the slide core and movable relative to the slide core; a first gate for injecting a hard first resin; and a first pin for injecting a soft second resin. With two gates,
The plurality of mold parts are closed and the slide core is advanced to form a plurality of spaces surrounded by the front surface of the slide core and the front end surface of the support pin. A primary injection molding cavity for primary injection of the first resin from the gate to form a plurality of primary injection molding portions, and the front end surface of the support pin near the end of the primary injection molding cavity portion The plurality of primary injection molding cavities are formed such that the ends of the adjacent primary injection molding cavities are positioned at a distance,
The primary injection-molded part that has been cured while the mold parts are closed is regulated by the plurality of mold parts, and a part of the outer surface of the primary injection-molded part is formed on the front end face without moving the support pin. Only the slide core is retracted in a supported state, and the overlapping surface composed of the exposed surface of the outer surface end part of which is supported at least by the front end surface of the support pin of the primary injection molding part, and the mold part are retracted. Forming a cavity for secondary injection molding consisting of a space surrounded by the slide core,
An injection mold characterized in that the overlapping surfaces of the adjacent primary injection molding parts are respectively located on a part of the projection surface of the cavity part for secondary injection molding projected from the moving direction of the slide core. Mold device.

Images